can I polish the chamber

ram1000 · December 10 2014 02:24:27 PM MST

of my Kimber 1911 10mm in hopes that it would allow the cartridge to feed in more reliably? Im having trouble with the thing FTF 50% of my hollow points. I polished the ramp and achieved better feed results for FMJ, but still no improvement for HP's. It seems to me that the case is gaining a friction bite about a third the way in as it slides off the magazine. They are always at an angle trying to slide into the chamber when they lock up the system.

Mike_Fontenot · December 10 2014 02:44:34 PM MST

My impression is that feedramp "slickness" is rarely the problem. More often, it's caused by the rear of the case needing to slide under the extractor, while being at an angle (because the bore axis is above the level of the top cartridge in the magazine). I think feeding is smoothest with minimum extractor tension (even better, with no extractor in the gun at all!). But if the tension is made as light as you'd like it to be for feeding, I think the extraction then gets erratic, perhaps down to no extraction at all. Catch 22!

ram1000 · December 10 2014 05:02:12 PM MST

Why would there be a difference between hollow point and FMJ then?

sqlbullet · December 10 2014 05:23:35 PM MST

Quote from: ram1000 on December 10 2014 05:02:12 PM MST
Why would there be a difference between hollow point and FMJ then?

Ogive.

I have found in my Para that most bullet shapes will not feed well if the COAL is greater than 1.250". Exactly the kind of FTF you are describing. It just gets bound up on the angle.

I have a few bullet shapes that are fine though. Among them are my Mountain Mold and NOE mold 200grain WFN designs. Those I can load as far out as will fit the magazine and they run fine. They have a noticeably different ogive than the HP and FMJ designs that don't feed.

If you are will to possibly trash a magazine, you can try altering the feed lips to release the cartridge head sooner. May or may not work. I had some para mags that had longer lips than the rest, so I trimmed them back to match the shortest factory mag I had. Helped a bit. But your results may vary. Your mag, your money if it doesn't work.

The_Shadow · December 10 2014 08:56:40 PM MST

The first thing to look at is the ammo itself...Does it fit a cartridge case gauge? The ammo has to be in spec., this would include factory and handloaded ammo as well.

I have seen case expansion just above the start of the extraction cut that has caused many issues, solution is pass through sizing.

Bullet profiles can hamper the feeding angle, depending on the cartridge overall length.

Recoil spring could be too strong and the slide is not staying back long enough or is returning too fast for the cartridge to orient itself to the chamber.

Be sure the extractor has not been damaged or bent. Dropping a round into the chamber and releasing the slide to have the extractor to jump over the extraction rim is a no no! Always feed from the magazine....

ram1000 · December 12 2014 09:26:38 AM MST

As far as ammo goes I have used PMC hollow points and Underwood hollow points and neither worked well, also using HSM FMJ which work about 99% since I polished the feed ramp.

10mmfan · December 12 2014 12:49:12 PM MST

Have you tried different mags? When I used wilson combat mags I had a similar problem.

ram1000 · December 15 2014 03:11:08 PM MST

Tried some Tripp mags with no advantageous effect, but I have sent my Kimber back as they have agreed to look at it.

DenStinett · December 15 2014 07:34:38 PM MST

Here's a Vid on Throat Polishing from Wilson Combat
This should help you quite a bit:
https://www.youtube.com/watch?v=yY71J8yGGcg

ram1000 · December 16 2014 02:17:57 PM MST

Thanks that shows a lot. Still wondering if there is any advantage or disadvantage to polishing the entire chamber all the way into the point where the case meets the barrel rifling???

DenStinett · December 19 2014 04:25:28 PM MST

Quote from: ram1000 on December 16 2014 02:17:57 PM MST
Thanks that shows a lot. Still wondering if there is any advantage or disadvantage to polishing the entire chamber all the way into the point where the case meets the barrel rifling???

No, not really
A nice Throat Job and (maybe) a slight bevel on the (underside of) Hood and you'll have the best of it

sw.sharpe · January 25 2015 07:36:13 PM MST

The basic problem is that 1911s and their variants, including the Kimber 10mm were designed for ball ammo. My understanding (based on the DVD series "Combat Customizing the 1911 Auto") is that the best solution is to stick with ball ammo or throat the barrel. See for example https://www.youtube.com/watch?v=yY71J8yGGcg. Obviously this is an invasive process and if done incorrectly will ruin the barrel and probably best left to an experienced gunsmith. Good luck.

Mike_Fontenot · January 26 2015 07:53:36 AM MST

After a local gunsmith did some "throating" on my chamber, I still was noticing that, when I slowly slid a cartridge up the feedramp with my fingers (while just holding the barrel with my other hand), the bullet was hesitating part way up. I could see some scuff marks on either side of the centerline on the feedramp, so I smoothed those off with some very fine emery paper, and the bullets then slid by smoothly. I don't understand how copper-jacketed lead JHP's could scratch hardened steel ... maybe it was from the snap-caps that I did some tests with ... those don't use real copper-jacketed lead bullets ... maybe they have some aluminum oxide on them, which might be harder than steel. Wish I could find some snap-caps that use real bullets (maybe FMJ's), and real brass cases. Anyway, for now the final result has been good ... I can slowly manually close the slide on a single real cartridge in my (round-follower) Kimber mags, and the cartridge now slides in like butter. I'm going to keep checking it, though, to be sure it stays that way.